Python 3.0 (a.k.a. "Python 3000" or "Py3k") is a new version of the language that is [img]http://incompatible[/img] with the 2.x line of releases. The language is mostly the same, but many details, especially how built-in objects like dictionaries and strings work, have changed considerably, and a lot of deprecated features have finally been removed. Also, the standard library has been reorganized in a few prominent places.